The airwaves in Iowa are filled with a lot of people saying some not very nice things about Newt Gingrich.

"Newt has a ton of baggage," states an ad from a group called Restore Our Future, a superPAC that supports former Massachusetts Gov. Mitt Romney. "He was fined $300,000 for ethics violations and took $1.6 million from Freddie Mac before it helped cause the economic meltdown. Newt supports amnesty for illegal immigrants and teamed with Nancy Pelosi and Al Gore on global warming."

Perhaps it's no surprise that Gingrich is losing ground in Iowa. A poll released Sunday by Public Policy Polling indicates a drop of 8 percentage points in one week, and 13 points in two weeks. Other polls show similar sharp drops in Gingrich's support.

"Rick Perry has blanketed the state with ads himself, plus there are ads running from an apparently pro-Romney superPAC and a pro-Rick Perry superPAC, and [former Pennsylvania Sen.] Rick Santorum has started some ads," said Drake University political science professor Dennis Goldford.

"Gingrich has simply had one ad in which he is so soft-spoken and gentle you expect honey and butterflies to flow from the television screen," said Goldford.

That image is far from the one Gingrich has publicly displayed most of his career, of a gloves-off, no-holds-barred fighter and bomb thrower. And Goldford says this "Newt-positive" ad doesn't seem to be working.

"There's just this wall of allegations about Gingrich's dealings, and his ads simply ignore those allegations and [try] to stay on the high road, but they become a little bit like an acid," said Goldford. "They start to eat away at the foundations of his support."

Gingrich, though, seems to be sticking with the kinder, gentler approach he put forward in his Iowa ad.

"I think positive ideas and positive solutions, the contract we've laid out at Newt.org, has attracted people," Gingrich said Sunday on CBS's Face The Nation. "I think they like the idea of somebody who's determined to be positive."

Gingrich faces another obstacle in halting his slide. His campaign lacks the resources to spend much on TV ads — even for a positive message. According to Politico, the Gingrich campaign is buying some $240,000 in airtime in Iowa. That compares with more than $800,000 being spent by Romney's superPAC and the Romney campaign, and big ad buys by Paul and Perry.

Monday in Iowa, Gingrich said one way he will respond to the negative ads is to hold daily telephone town halls, and he plans a multicity bus tour of the state before the Jan. 3 caucuses.

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Has Newt Gingrich peaked? A new round of polling suggests the former House speaker has fallen from the front of the pack nationally and in Iowa. Republican caucuses take place there just two weeks from tomorrow. And one polls shows Ron Paul is now the top choice among Iowa Republicans. Paul is one of several GOP candidates who've been running tough ads, attacking Gingrich in Iowa, while Gingrich has been staying positive. Here's NPR's Brian Naylor.

BRIAN NAYLOR, BYLINE: The airwaves in Iowa are filled with a lot of people saying some not very nice things about Newt Gingrich. This is from a group called Restore Our Future, a Super PAC that supports former Massachusetts Governor Mitt Romney.

NAYLOR: This ad is from Texas Congressman Ron Paul that uses a montage of news clips and the Speaker's own words to attack him.

(SOUNDBITE OF POLITICAL AD)

NAYLOR: So perhaps it's no surprise that Gingrich is losing ground in Iowa. The latest PPP poll indicates a drop of eight points since their survey a week ago. Other polls have shown similar sharp drops in Gingrich's support. Political science professor Dennis Goldford of Drake University in Des Moines says there's a correlation between Gingrich's decline and the negative ads of his opponents.

DENNIS GOLDFORD: Gingrich has had simply one ad in which he is so soft spoken and gentle, you expect honey and butterflies to flow from the television screen. This isn't the Newt Gingrich that most people know or imagine.

(SOUNDBITE OF POLITICAL AD)

NAYLOR: That image is far from the one Gingrich has publicly displayed, if not honed, most of his career: a gloves off, no holds barred fighter and rhetorical bomb thrower. And Goldford says the ad doesn't seem to be working.

GOLDFORD: There's just this wall of allegation about Gingrich's dealings, and his ads simply ignores those allegations and tries to stay on the high road. But they become a little bit like an acid. They start to eat away at the foundations of his support.

NAYLOR: Gingrich though seems to be sticking with the kindler, gentler approach he put forward in his Iowa ad. Speaking yesterday on CBS's "Face the Nation," Gingrich gave no evidence he was thinking of changing a thing.

(SOUNDBITE OF TV SHOW, "FACE THE NATION")

NAYLOR: Gingrich faces another obstacle to halting his slide: his campaign appears to lack the resources to spend much on TV ads, even for a positive message. According to a story in Politico, the Gingrich campaign is buying some $240,000 in airtime in Iowa. That compares to over $800,000 being spent by Romney's Super PAC and the Romney campaign. Today in Iowa, Gingrich said one more way he'll be responding to the negative ads is to hold daily telephone town halls, and he plans a multi-city bus tour between now and January 3rd. Brian Naylor, NPR News. Transcript provided by NPR, Copyright NPR.